Reinforcement for sections of embedded conduits subject to external pressure



April 13, 1954 A. FORTES REINFORCEMENT FOR SECTIONS OF EMBEDDED 2,674,857 Eiled Oct. 4, 1948 CONDUITS SUBJECT TO EXTERNAL PRESSURE 2 Sheets-Sheet 1 April 13, 1954 Filed Oct. 4, 1948 A. FORTES REINFORCEMENT FOR SECTIONS OF EMBEDDED CONDUITS SUBJE CT T0 EXTERNAL PRESSURE I 2 Sheets-Sheet 2 I Patented Apr. 13, 1954 REINFORCEMENT FOR SECTIONS OF EM- BEDDED CONDUITS SUBJECT TO EXTER- N-AL PRESSURE Angelo. Fortes, Lisbon, Portugal, assignor of onehalf to Neyrpic Portuguesa, Limitada, Lisbon, Portugal, a corporation of Portugal Application October 4, 1948, Serial No. 52,656

Claims priority, application Portugal October 9, 1947' 11 Claims.

The invention relates to reinforcements for sections of embedded conduits subject to external pressure.

Conduits which extend through large masses plates are used, and the reinforcement is welded on to them, in the workshop or on the spot. The reinforcing webs should be of a length at least equal to half the distance between two adjoining such as water dams are subject to considerable 5 webs, measured around the outer circumference external pressure sometimes known as sub-presof the conduit. Should exceptional strength be sure and reinforcing of the conduits is required, desired smaller webs may be welded to the outer particularly where the mass in which the conduit surface of the conduit between the larger webs is embedded is a porous mass, as in a dam, or and parallel to the axis of the conduit. there is a space between the conduit and the The invention will now be described with refmass so that the head race may exert a considerence to the accompanying drawings in which: erable static pressure on the outer surface of Figure I illustrates a conduit having webs the conduit when it is empty or whenever the formed by fiat plates extending in line over more internal pressure drops unduly because of a than one section. strong increase in the fiow or any other hydraulic i5 Figure II illustrates a conduit having reinforcphenomenon. ing webs of the type illustrated in Figure I, stag- The need for reinforcing of such conduits has gered on adjacent sections. been recognized but until now the reinforcements Figure III illustrates in detail a web which is have consisted of flat or section iron or circular bent adjacent its free edge at an angle to the trussed beams either of metal or concrete exremainder of the web. tending aboutthe circumference of the conduits Figure IV illustrates a modification of the web or even reinforced concrete circular beams or according to Figure III. sheaths. Large numbers of tie rods of different Figure V illustrates afurther embodiment of shapes have also been used, fixed to the periphery the invention in which the web is corrugated. of the conduit in order to secure it to the sur- 35 Figure VI illustrates an arrangement in which rounding concrete of the dam or the like but all the web is connected by means of stirrups to rods of these reinforcements have been subject to obembedded in the enveloping concrete. jections arising principally from the inaccuracy Figure VII illustrates an embodiment of the of calculations as to their strength, thus making invention in which the webs are plain beams. it necessary to adopt high safety factors with Figure -VIII illustrates an embodiment of the consequent increase in the weight of the entire invention in W ch h We s are r s d b a structure and increase in cost. The circumferand entially extending reinforcements or the large Figure IX illustrates an modification of the innumbers of tie rods are also subject to the disvention in which smaller webs are provided beadvantage that they are difiicult to construct tween the larger webs for exceptional strength. and erect and they are therefore unduly expen- Referring to Figu s I and the Conduit l sive. is provided with the webs 2 extending longitudi- Accordingly the principal object of the invenn lly of the c nduit nd it h r ali ned over adtion is to provide a relatively inexpensive reinjacent conduit sections 3 and 4, as illustrated in forcement for conduits of the type described Figure I, or staggered, as illustrated in Figure which is free from the disadvantages referred to II. In Figures I and II the webs are fiat plates b continuously welded along one edge to the outer More specifically it is an object of the invention surface of the conduit. The webs illustrated in to provide a reinforcement for conduits of the Figures III to V are similarly welded along one type described which dispenses with the circumedge but in Figures III to V are shaped to increase ferentially extending members and avoids the the concrete slip resistance and in Figure VI are construction and erection difficulties referred to connected by stirrups 5 to rods 6 embedded in above. the enveloping concrete. ,In Figures VII and VIII With these and other objects in view the rein the webs are plain and trussed beams, respecforcement according to the invention comprises tively, and in Figure IX, smaller webs l are continuous webs fixed upon the outer surface of welded or otherwise secured to the outside of the the conduit and extending lengthwise thereof, conduit parallel to the axis thereof.. (i. e. along its generatrices) over a single or sev- Other embodiments of the invention are coneral sections of conduit. templated without departing from the main idea In most cases, conduits of welded or riveted of the invention, which consists in placing webs extending longitudinally of the conduit along its outer surface so as to extend continuously throughout at least each section, in contrast to the existing arrangements in which the reinforcingmembers extend circumferentially and are spaced longitudinally of the conduit.

According to the invention the cross section of the various conduit sections remains constant throughout the entire length of the section, thus simplifying the strength calculations which are reduced to a two dimensional problem and moreover are accurate because no approximations of any sort are required. This simplification and precision in the strength calculations makes it unnecessary to provide for excessive safety factors and thus avoids unnecessary weight and therefore unnecessary expense. At the same time the reinforcing webs are in themselves simple to construct and may be plates currently obtainable in the market and welded in a simple manner to the conduits with welding fillets either in the shop or on the job. Thus the webs themselves are less expensive and they are much less expensive to install, and finally the conduit sections between two consecutive longitudinal reinforcing webs act as arches having their abutments resting on the webs, thus providing a greater resistance to external pressure for a given thickness of conduit wall.

What I claim is:

1. An arrangement for reinforcing conduit to be embedded in concrete or the like and subject to external pressure, comprising a multiplicity of continuous metal webs fixedly positioned, upon the outer surface of a cylindrical conduit and extending along generatrices thereof.

2. Reinforcement as claimed in claim 1 in which said webs are flat plates set on edge and extending generally radially from the circumference of the conduit.

p 3. Reinforcement as claimed in claim 1 --in which said webs are corrugated plates set on edge and extending generally radially from the circumference of the conduit. r

4. Reinforcement as claimed in claim 1 in which the webs are plain beams.

5. Reinforcement as claimed in claim 1 in which the webs are trussed beams.

6. Reinforcement as claimed in claim 1 in which the length of a web is at least equal to half the distance between two adjoining webs, measured circumferentially of the conduit.

7. An embedded conduit structure subject to external pressure comprising a cylindrical conduit, a plurality of continuous webs fixedly positioned on the outer surface of said conduit and extending along the generatrices thereof, and

embedding material surrounding said conduit and webs whereby the external pressure on said conduit will be transmitted through said webs to said embedding material.

8. A conduit structure to be embedded in concrete or the like and. subject to external pressure comprising a cylindrical conduit and a plurality of continuous webs fixedly positioned upon the outer surface of the conduit and extending along the generatrices thereof so as to define longitudinally-extending arch-like sections in the conduit therebetween; said webs being plates set on edge and extending generally radially from the circumference of the conduit, said plates being bent adjacent their free edges at an angle to the remainder of the plate so that the bent portions of the plates when embedded in the surrounding concrete form a support for the arch-like sections, whereby the resistance of the conduit to buckling or collapse is greatly increased.

9. A method of reinforcing a conduit for em bedding in concrete comprising the steps of welding a plurality of continuous webs on the outer surface of said conduit, extending along the generatrices thereof, and embedding said conduit in concrete.

10. A method of reinforcing a conduit for embedding in concrete comprising the steps of attaching a plurality of continuous webs in an axial direction along the outer-surface of said conduit, forming bends along the lengths of said webs, and embedding said conduit in concrete.

11. A method of reinforcing a cylindrical conduit for embedding in concrete comprising the steps of attaching a plurality of continuous webs along the outer surface of said conduit, extending along the generatrices thereof, and embedding said conduit in concrete.

References Cited in the file of this patent UNITED. STATES PATENTS Number Name Date D. 26,842 l-lawley Mar, 30, 1897 177,586 Strecker May 16, 1876 813,918 Schrnitz Q. Feb. 27, 1906 971,353 Brayton et a1 Sept. 27, 1910 1,096,993 Boyd May 19, 1914 2,067,493 Kinzie Jan. 12, 1937 2,236,185 Murray Mar. 25, 1941 2,389,166 SeaVer Nov, 20, 1945 FOREIGN PATENTS Number Country Date 5,164 Great Britain Dec. 10, 1880 688,641 France Aug. 27, 1930 619,435 Germany of 1935 857,557 France of 1940 

